Typically, a hydrocarbon producing well will include a subsurface safety valve to seal off a section of production tubing in the event of an emergency, e.g., damage to the well head. This type of valve is usually activated from the surface using a hydraulic control system with control lines that run from the surface to the subsurface safety valve. The valve typically comprises a valve housing and a closure member used to seal the production tubing in the well bore. The closure member typically used is a flapper which is hingedly attached to the valve housing and rotatable throughout an arc of ninety degrees between an open and closed position. The control system uses hydraulic pressure to move a hollow tube, usually referred to as a flowtube, downwardly against the flapper and a return spring, thereby disposing the flapper in an open position such that hydrocarbons may flow in the production tubing. Once, the hydraulic pressure is lost in the system, the flow tube moves upwardly thereby allowing the return spring to bias the flapper in a closed position effectively sealing off from the surface the flow of hydrocarbons in the production tubing.
Once the flapper is in the closed position, formation pressure accumulates on the upstream side of the flapper. This increase in pressure causes a high pressure differential across the flapper making the opening of the flapper difficult. One manner to solve this problem is to incorporate an equalizing or bleed valve assembly in the flapper. Such an equalizing valve assembly typically comprises a plunger or like member, a spring, and hardware to fasten the spring and plunger to the flapper. The plunger, typically biased against the flapper by the spring, is displaced to allow the pressure differential to dissipate across the flapper thereby reducing the difficulty in disposing the flapper in an open position.